Oil boiler Thermostat problem

[pat1mac]

Hi, I've inherited an old oil boiler, must be 20 years + old, Falcon Series 2, (Stelrad Group), that's just developed problem with the boiler thermostat. ( at least I think its this ). The central heating was previously causing problems with some rads being cooler than others, but thanks to great advice from this forum thats now cleared. This problem arose after I tried to clear up the wiring around the boiler ( I know, leave well alone you might say!") but the pump was running all the time, wires all over the place etc. Anyway, following my fantastic rewire the boiler themostat didn't work, temp of the boiler ouput shot up to 100C. I restored the wiring back to previous state, but now the boiler temp only reached 65/70C, although it does switch of now. (the room stat still calls for heat). The boiler stat is set to max as well.
I can't find any details of this boiler anywhere, maybe the themostat is malfunctioning, any ideas on what to do, or where I can get details of this boiler ?.
I'm also concerned that the original wiring is correct.
There are 3 wires attached to the boiler. One power in from the timer, one from room stat, and one other with power, not sure ifs it power in/ out. Pump on all time.

 

[Terrywookfit]

I doubt that boiler stat is faulty, as they normally lose their charge and fail HOT!
More info on system required.

Is it gravity circs .
How many M/v's etc?

If basic gravity system H/water on will control burner via boilers stat (s).

Htg on will control pump via R /stat

 

[pat1mac]

Hi Terry, Boiler is in a shed near the house. Its not gravity fed but runs the C/H via a pump, 12 rads mostly on TRV's , with a cylinder at the end of the run ( Historic reasons since the cylinder can also be fed from a stove as well ). You cannot have hot water seperately. The pump comes on with the timer. The boiler also has an input from a thermostat in the hall, with calls for heat most of the time. The boiler switches on & off when it reaches its set boiler thermostat setting. Its a really old boiler but I want to try and get it going, rather then replace it as present. Rads are not as hot as they were before due to perhaps the boiler temp being a bit lower than it should. I cannot increase the boiler temp due to the Boiler thermostat being set to max.

 

[pat1mac]

PS No TRV's etc, its a very old simple system simply feeding C?h and cylinder together, with only control appears to be room stat and boiler stat.